The antennas of mobile telephones are typically made to be broadband and 50-Ohm. Power regulation is made by varying the output voltage of the output stage. The amplifier is also often 50-Ohm, in which case most of the loss of power is in the loss from the output stage. If the amplifier can be made low-impedance and the operating voltage can be regulated, a considerable saving in power will be obtained, at least at high power levels. Due to the aforementioned adaptation, this is not, however, done. Especially in mobile telephones, all excess power consumption is bad, as it reduces the operating time of the telephone's battery.
Broadband antennas require expensive bandpass filters, typically implemented using SAW technology, which increase the total cost of the electronics.